A comedy about a group of unlikely burglars who stole the Stone of Destiny from Westminster Abbey 58 years ago is set to become a secret weapon in Scotland's fight for independence, according to one of the original conspirators.

Ian Hamilton, 83, was one of four students from Glasgow University who 'repatriated' the stone on Christmas Day 1950. He later became a Scottish QC and SNP activist and wrote a book about the incident which inspired the film The Stone of Destiny, which he believes will hasten the end of the United Kingdom.

The film - starring Charlie Cox, Billy Boyd and Robert Carlyle - will be shown at the Edinburgh International Film Festival next month, with Sir Sean Connery expected to attend, and is due to be distributed across the UK later in the year. 'The producer told me that anyone who sees this film will leave the cinema a Scottish nationalist,' Hamilton said with relish. 'I am just so delighted that after all these years what we did has real relevance again.'

The burglary was laden with symbolism, as it was on this stone that all Scottish kings were crowned until 1296 when it was moved from Scone Palace to London by a triumphant King Edward I as spoils of war. Since then all British monarchs have been crowned over the stone, and although it was moved to Edinburgh in 1996 it is expected to be taken back to London for any future coronation.

Hamilton believes he would have been thrown in prison for taking the 336lb lump of sandstone had Westminster not feared a Scottish revolution.

'We are so close to independence now I couldn't be happier that this film and my book seem to be having their moment again,' he told The Observer last night. 'For years I was known as the "Stone Man" and I kept away from the subject because it was too big. But now I am old I can enjoy it again.

'There is a myth that they didn't prosecute us because there was a doubt over who owned the stone. But that was just a story they put out about it. The fact was the Labour Home Office minister James Chuter-Ede, and Sir Hartley Shawcross, the Attorney General, believed that, if they prosecuted us, Scots would take to the streets in our defence. The last thing they wanted was an uprising.'

His book, the basis for American writer-director Charles Martin Smith's new film, is to be reissued on 9 June.

The theft of the Stone of Destiny has an almost mythic status among Scottish nationalists. 'The idea of Scotland as a nation was completely dead in 1950,' Hamilton said. 'It was a time when more than 45 per cent of Scots voted Tory - the party most associated with the union.'

Driven to make a bold statement about their country, Hamilton and three other members of a pro-independence group, the Scottish Covenant Association - engineering students Gavin Vernon and Alan Stuart, and a domestic science student, Kay Matheson - drove to London to steal the stone.

Vernon, who emigrated to Vancouver, died two years ago; Stuart is believed to live on the west coast of Scotland; while Kay Matheson is living in a care home.

'This was before the days of high security,' Hamilton explained. 'We took a jemmy with us to get through the door, and although there was one guard floating around he spent most of his time making cups of tea.'

During the theft the stone broke into two pieces and it was later repaired by a stonemason. Using two cars, the group avoided roadblocks on the way north and for a period hid part of the stone in a field. On 11 April, 1951, they left the stone on the altar of Arbroath Abbey.

Today Hamilton is less of a republican than he used to be: he believes a Scottish nation would want to retain the monarchy. However, he has made a point of never seeing the Stone of Destiny again. 'I've always said I wouldn't go and see it unless we had won independence,' he said. 'But we seem so close to that now I'd probably make an exception if the First Minister invited me to take a look.'